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Friday, 3 June 2016

RTL on HF? no way!

Well,

I read with interest an article in Practical Wireless from June 2016 describing a neat looking receive converter to be placed up front of an RTL dongle type receiver.

These RTL devices are easy to find for a few GBP:



Here's the schematic of the converter:


And its built on a PCB from OHS Park which cost a staggering $5 USD for 3 including postage to the UK. They were delivered in a very timely manner too! 


You will see that I have actually built two - but basically we have a 50MHz oscillator and a mixer, so in the example below my SDR would be tuned to 70MHz and I would be listening to my signal generator on 20MHz. The output contains what you would expect from a mixer in that we have the input frequency, the on board oscillator frequency, their sum, their difference and all the other harmonics from this mixing process:


More to follow once I have it up and running with the RTL dongle, but so far so good!

Local conditions.

3 comments:

  1. Hi, mark, it is vu3zmv again.
    please see the no hardware patch in link below.
    http://www.rtl-sdr.com/direct-sampling-mode-hardware-modifcations/

    i am using this. you can please analyse its performance.
    . Incidntally if you own any rtl sdr with R820T2, the performance could be better.
    However with a small pre amp at input, we get same performance.
    all the best for all the wonderful lab experiments you are conducting and I feel as if i am in your lab too while reading your articles.
    regrads
    sarma
    vu3zmv

    ReplyDelete
  2. Hi mark. I was very interested in your blog RTL on HF.
    Unfortunally, i can 't find more info to the article on
    Practical Wireless or other source. I have build several HF converters, link on my site 'on1bes' . Please, have you a name of the autor in the P.W. magazine, or a copy of the article ?
    regards, on1bes Scarlet.be

    ReplyDelete
    Replies
    1. its in June 2016 and the author is Jemnny List G7CKF

      Delete